Pharmacology

Captopril

Competitively inhibits angiotensin I-converting enzyme, resulting in the prevention of angiotensin I conversion to angiotensin II, a potent vasoconstrictor that also stimulates aldosterone secretion. This action results in a decrease in sodium and fluid retention, increase in diuresis, and a decrease in BP.

Hydrochlorothiazide

Increases chloride, sodium, and water excretion by interfering with transport of sodium ions across renal tubular epithelium.

Indications and Usage

Treatment of hypertension.

Contraindications

Anuric patients; history of angioedema; patients hypersensitive to captopril or any other ACE inhibitor, hydrochlorothiazide, or other sulfonamide derivative.

Dosage and Administration

Adults

PO captopril/hydrochlorothiazide may be substituted for previously titrated individual components. Alternatively, therapy may be started with a single captopril/hydrochlorothiazide tablet (25 mg captopril combined with 15 mg hydrochlorothiazide) every day. For patients not responding sufficiently, the dose may be titrated upward, usually at 6-wk intervals. Maximum daily dose should not exceed 150 mg of captopril or 50 mg of hydrochlorothiazide.

Precautions

Warnings

When used in pregnancy during the second and third trimesters, ACE inhibitors can cause injury and even death to the developing fetus. When pregnancy is detected, discontinue therapy as soon as possible.

Monitor

Blood sugar

Monitor blood sugar in diabetic patient when drug is started or dose is changed. Report significant changes to health care provider.

BP

Monitor and record BP and pulse. Should hypotension result, hold medication and notify health care provider.

Serum electrolytes

Ensure that serum electrolytes are monitored periodically.

WBC

Ensure that WBC with differential is determined prior to starting treatment, every 2 wk for 3 mo, and periodically thereafter in hypertensive patients with renal function impairment or CHF.

Pregnancy

Category D (second and third trimester); Category C (first trimester). ACE inhibitors (eg, captopril) can cause injury or death to fetus if used during second or third trimester. When pregnancy is detected, discontinue as soon as possible.

Lactation

Excreted in breast milk.

Children

Safety and efficacy not established.

Renal Function

Use with caution.

Hepatic Function

Use with caution.

Angioedema

Use with extreme caution in patients with hereditary angioedema. Angioedema associated with laryngeal edema may be fatal.

Hypotension

Decreases in BP may occur, especially in salt- or volume-depleted patients as a result of dialysis, prolonged diuretic therapy, dietary salt restriction, diarrhea, or vomiting. Volume and salt depletion should be corrected before initiating therapy with benazepril/hydrochlorothiazide.

Advise patient to monitor and record BP and pulse at home and to inform health care provider if abnormal measurements are noted. Also advise patient to take record of BP and pulse to each follow-up visit.

Emphasize to hypertensive patient importance of other modalities on BP: weight control, regular exercise, smoking cessation, and moderate intake of alcohol and salt.

Instruct patient to stop taking drug and immediately report any of the following symptoms to health care provider: persistent cough; fainting; swelling of the face, lips, eyelids or tongue; sore throat; fever or other signs of infection; yellowing of skin or eyes; persistent nausea or vomiting; swelling of the feet or ankles.

Caution patient to not take any prescription or OTC medications, salt substitutes, or dietary supplements unless advised by health care provider.